Grammatical comprehension, aphasic syndromes and neuroimaging

Abstract

This paper presents grammatical comprehension, computerized tomography (CT) and positron emission tomography (PET) data from a group of 43 aphasic patients. Comparison of comprehension performance with structural lesion (CT) revealed a correlation between comprehension of syntax and one inferior frontal lobe region (Broca's area) and one temporal lobe region (Wernicke's area). In contrast, comparison between comprehension performance and metabolic data demonstrated strong correlations between morphology and syntax comprehension and regional measures throughout the temporal, parietal and occipital lobes. The second aspect of the study looked at performance differences between diagnostic groups of aphasic patients. Very few behavioral differences were observed between aphasic groups (Broca's, Anomic, Conduction and Wernicke's), other than differences in severity. On all measures, Broca's and Wernicke's patients performed similarly. Overall, the findings support a model of brain—behavior relations in which language comprehension is represented by more widespread regions of the left hemisphere than is traditionally thought, and the aphasie syndromes differ from each other less than is traditionally believed.